Carburetor



April 18, 1933. C. H KIRBY 1,904,002

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Filed Aug. .6; 192s s sheets-sheet 5 mun.

Patented Apr. 18, 1933 UNITED *.a'lixfles` PATENT o1-"Fica CHARLES II. KIRBY, or FLINT, MICHIGAN, AssIGNoB. 'ro MARVEL. CARBURETER COMPANY, or FIJINT, MICHIGAN, A CORPORATION or ILLINOIS cAnBUnETon Applcation-led August 6, 1928.. Serial No. 297,696.

This invention relates to improvements in carburetors of the type in which an auxiliary jet or nozzle constantly supp-lies'fuel' to the mixture passageway in varying quantities,

5 during the running of the engine with which the carburetor is associated.

In my copending application, led-Aug.'

6,1928, serial No. 297,695, I have disclosed a novel carburetor-provided with an auxil-Y modified in its extent by a slightly sub-atmospheric pressure in a chamber communicatingrwith the auxiliary fuel passageway.V

This sub-atmospheric` pressure is brought about by positioning an opening in theentering lip of the Venturil tube of the-carburetor, and putting this opening -in communication with said chamber; the degree of the sub-atmospheric pressure being'greater as the velocity of the air entering the Venturi tube is increased. y In the structure disclosed in said application, instant acceleration is obtained by a U-tube, which is also controlled to somey extent, by the sub-atmospheric pressure above mentioned, so that the higher the speed of the motor, the less the additionall discharge for acceleration purposes.

Said application also shows a well for augmenting the U-tube supply kduring accelera.- tion, and the primary object of the present lo invention is to provide in such a carbure-- tor, additional means for the purpose` of intermediately prolonging the accelerating charge to lill the hiatus between the emptyingof the reserve leg of the U-tube, and the r beginning of operations from the well. VVThis result is brought about by a concentricannular chamber, arranged around the reserve leg of the U-tube, Yand this chamber is provided with al small orifice to permitv air to enterthe chamber slowly, and in this way,

the fuel therein will be held back temporarily, and subsequently follow up the fuel after it leaves the reserve leg, and the rate Y of the discharge will be dependent `on the size of said orifice and the position of the hole in the Venturi tube. Another object lof the present invention is to combine-in a carburetor, a U-tube functioning toinstantaneously supply an accelerating charge when needed; a well to furnish 6@ an auxiliary accelerating charge, and an annular chamber tofurnish acceleratingfuel during the interim between the feed from the reserve leg. of the U-tube and said well.

Another object of theinvention is to pro-` 65. vide accelerating fuel supply means of thel above mentionedcharacter, combined with a passageway opening into the entrance lip of the Venturi tube, whereby the air travel-y ling through the Venturi tube will modify i705 the accelerating feed from the reserve leg, annular chamber and well. Y

The invention will now bedescribed in de-ftail, in connection with the accompanying drawings, in which, I I ,75

`Fig.'1 is a vertical sectional view, partly in elevation, of a form of the invention designed more especiallyA with a view of clearly illusf trating the invention-and showing the throttle .valveV closed. i Y

Figs. 2, 3 and i aresimilar views with cer-- tain-parts omitted, and illustrating 'the varying fuel-levels in the reserve leg, annular chamber and well, as the throttle' is moved from closed to open position during acceleration.

Fig. -is a transverse sectional view vof a portion of acommercialembodiment.

Fig. 6 is a similar view of another coni-Y mercial embodiment, and illustrating a mo'd- 90 .ification of the main fuel control valve. Y

In the embodiment of thevinvention illus= trated in Figs. l to 4' inclusive, l designates a fioatchamber to which the liquid fuel is fed bya pipe 2. A iioat 3 in the chamber, op- 95 erates a Valve i in the ordinary manner to control the feeding of the'fuel from the pipe. into the chamber. c

As set forthV in my above mentioned copending application, fuel from the chamber 1, while the engine is running, is continuously fed through a tube 5, and orifice member 6, to a chamber 7, from which it passes through a duct 8 that discharges into the main mixture passageway 9 of the carburetor, above the pivoted throttle valve 10. This feed varies, due to the fact that the chamber 11, containing the tube 5, communicates with an aperture 12 in the entrance lip of a Venturi tube or throat 13, by means of ports 14, 15 and 16,'and compartments'l and 18.

It will be readily appreciated by those skilled in the art, that the suction exerted at 12, will vary when the throttle valve is in dierent positions. lVhen the throttle is in the position shown in Fig. 1, the suction in 12 will be at a minimum, and the feed through 8 will be at a maximum. On the other hand, when the throttle is fully opened,

as shown in Fig. 4, the suction in 12 will be at a maximum, and consequently, subatmospheric pressure through 14-18, will be communicated to the chamber-11, so that the feed through 8 will be at a minimum. Consequently, movements of the throttle will func-V tion to vary the feed through 8, such feed gradually diminishing as the throttle is moved from closed to open position.

In the copending application, I have also disclosed a'U-tube structure, consisting of a horizontal passageway 19, a main leg 20, and a reserve leg 21. The main leg forms the main nozzle of the carburetor, and its discharge end 22 terminates within the restricted portion of the Venturi throat. The reserve leg 21 is adapted, when the motor is not `running, to fill up to the level 23 with fuel, so that when the motor is started, the fuel from this reserve leg will be immediately withdrawn, as shown in Fig. 2,'to' furnish a rich starting mixture. The air enters the mixture passageway through its inlet end 24.

The fuel i`s` fed from the chamber 1 to the passageway 19, through ya conduit 25, in which orifice members 26, and 27 are interposed, and a needle valve 28 is employed to regulate the passage of fuel through thel orifice member 27. A well 29 is located in the chamber 17, and communicates with the con-- duit 25 by a port 30, and when the engine is latter through a small port 36 which placesv the lower end of the annular chamber in communication with the interior ofthe reserve leg. A port 37 in the upper end ofl the reserve leg,iplaces the top portion of the annular chamber in communication with the will be emptied next, and finally the well 29 will be emptied.- Of course, the emptying of these parts will be influenced b-y the suction exerted through 12, but 'as the discharge end 22 of the main nozzle is right in the restricted Yportion of the Venturi tube, the suction at 22 'will always be greater than that at 12, when the throttle 10 is opened to any degree.

By viewing Figs. 2, 3 and 4 at this time, it may be seen that asfthe throttle is opened, the feed through 8 will gradually diminish without ceasing entirely, and that after the fuel is discharged from the reserve leg 21,

it will then be discharged from the annular chamber 34, and finally from the well 29. When the throttle valve isiin the position shownin Fig. 4, if. the valve is kept open, then the main feed will be through 25, 19 and 20, and the auxiliary feed through 8.

With regard tothe commercial embodiments of the invention, it will be recognized that for the purpose of compactness and mechanical expediency, it is advisable toplace the parts 21, 29 and 5 at different points around' the'main `passageway 9, instead of all in the same vertical plane as shown in Fig. 1, `and in my before mentioned copending application, I have fully-disclosed such an embodiment. Y Howeverf the structure Y shown in Fig. 5 differs from that illustrated.

in my copending application, owing to the addition of the annular chamber 'for feeding the intermediate auxiliary supply. As shown in Fig. 5, the main leg or nozzle 20a communicates with its supply passageway 19a, but said passageway extends laterally instead of longitudinally, as in Fig. 1. Furthermore, the reserve leg 21al forming art of the U-tube, is arranged to one side ofp the carburetor, instead of betweenV the float chamber andthe main passageway. In this embodiment, the tube 33a surroun-ds the reserve leg to form the annular chamber 34a, and the fuel entersV and leav-es the annular chamber through a port 36a, while theair enters and leaves by the port370a.V In this form -of the invention, 12a indicates the port in the entrance lip of the Venturi tube, which is utilizedto maintaink sub-atmospheric pressure in the passageway 12?). In this form of the invention, the orificemember 27a corresponding with the member 27 in Fig. V1, is not used in connection with the needle valve,

while in Fig. 6, the needle valve 285 cooperates with the orifice member- 276. It may thus be seen that th-e needle valve may cooperate with either one of the orifice members arranged in the main supply line between the iioat chamber and the main fuel nozzle.

It is believed that thos-e skilled in the artl may readily understand the invention from the foregoing description when taken in con-v with the mixture passageway for placing sub-atmospheric pressure on the primary and reserve supplies to modify the feeds from the same as the throttle valve is moved.

2. In a carburetor, a mixture passageway, a throttle valve in the passageway, fuel supply means, means influenced by movements of the throttle valve for feeding fuel from the supply into the passageway posterior to the throttle valve, a fuel nozzle extending into the passageway, a reserve leg for supplying auxiliary fuel to the nozzle during acceleration, means for conducting fuel from the supply to the reserve leg and nozzle, a chamber for a reserve supply of fuel, and means for feeding fuel to and from said chamber through the reserve leg.

3. In a carburetor,l a mixture passageway, a single fuel nozzle extending into the passageway, a throttle valve controlling the iiow of mixture through the passageway, main and a plurality of reserve means for supplying auxiliary fuel to the nozzle, and means controlled by suction exerted in the mixture passageway for regulating the feed of fuel from the main and reserve supplies to the nozzle.

4. In a carburetor, a'mixture passageway, a single fuel nozzle extending intothe passageway, a reserve fuel leg,ymeans for supplying fuel to the reserve leg and main nozzle, an annular chamber surrounding the reserve leg, means for flowing' fuel from the apply to the annular chamber, means for causing fuel to flow fromthe annular chamber to the main nozzle, after the fuel fromY the reserve leg has been fed to the nozzle and means communicating with the mixture passageway for placing subatmospheric pressure on the fuel in the reserve leg and annular chamber by the velocity of air passing through said mixture passageway to modify the/feeds from the sameasthe throttle valve is moved.n f Y i n-In'a carburetor, a mixture passageway and'a`pairofcompartments, a .U-tube including avreserve'leg arranged in one of said cempartments, anda main nozzle extending into the mixture passageway,'the other compart-ment forming a well, means for supplying fuel'to th-e well and U-tube, and placing the well and U-tube in communication, an annular chamber in one of the compartments surrounding the reserve leg and adapted to contain .a reserve supply of fuel, a throttle valve in the mixturepassageway, and means controlled' by the opening of the throttle for feeding fuel from the reserve leg, annular chamber and well, to said nozzle.

6. ,Inra carburetor', a carbureting passage having a throttle valve therein and provided with` independent meansfor feeding fuel into said carbureting passage above and below thethrottle valve, a main supply-chamber, a fuel passage leading therefrom, a U tube in communication with said supply passage including a main leOv and a reserve leg, the main leg extending into said carbureting passage and forming the only means forv feeding fuel into said passage .below the throttle valve, a well in communication with said fuel supply passage, a reserve chamber and means for feeding fuel to and from said reserve chamber through said U tube.

7. In a carburetor having a constant level reservoir, a carbureting passage, a fuel nozzle extending into said carbureting passage, means for feeding fuel constantly from said constant level reservoir to said nozzle, means for feeding primary and auxiliary supplies of fuel to said nozzle during acceleration, means for furnishing an additional accelerating supply to said nozzle during the interim between' the feeds of the primary and auxiliary supplies and a passage extending from said primary and auxiliary supplies to said carbureting passage and terminating in a port entering said passage in a reverse direction to the path of air passing therethrough for placing subatmospheric pressure on the primary and auxiliary supplies by the velocity of` air passing through vsaid carbureting passage.

8V. VIn a carburetor havingv a constant level reservoir, a carbureting passage kprovided with a throttle valve, a venturi disposed in said'carbureting passage, a fuel nozzle extending int'o said Venturi tube, means for furnishing a primary supply of fuel to said nozzles vduring acceleration caused bythe opening of the throttle yvalve and means for furnishingV an additional charge of fuel to the main nozzle during' the interim between kthe supply of primary and auxiliary charges iso and means including a passageway communicating with the carbureting passage in a direction reverse to the travel of air passing therethrough for placing subatmospherie pressure on the primary and reserve supplies by the velocity of air passing through said passageway to modify the feeds from the same as the throttle valve is moved.

9. Ina Carburetor having a constant level reservoir, a earbureting passage having a throttle valve for controlling the passage of explosive mixture therethrough, a nozzle supplied constantly with fuel from said constant level reservoir, meansfor normally metering the supply of fuel to said nozzle, a plurality of auxiliary reservoirs for successively supplying fuel to said nozzle and means forvco'ntrolling the supply of fuel delivered to .said nozzle from said plurality of auxiliary reservoirs by the velocity of air passing through said carbureting passage.

- In testimony whereof I hereunto aix my signature.

. CHARLES H. KIRBY. 

